Isolation of Chlamydia trachomatis from different areas of conjunctiva in relation to intensity of hyperendemic trachoma in school children in Southern Tunisia.

The simplified one-passage technique of culture in irradiated McCoy cells, in conjunction with certain other developments in technique, was used to isolate Chlamydia trachomatis from specimens collected from 78 children with trachoma in Douz, Southern Tunisia. The results show that C. trachomatis is not confined to the upper tarsal area of the conjunctiva in hyperendemic trachoma. The higher isolation rate and corresponding increase in the number of inclusions obtained from swabbings of the upper fornix and lower lid in addition to the conventional collection from the upper tarsus show the superiority of collecting specimens for culture from the whole conjunctiva. Specimens could be collected from the whole conjunctiva by using 1 swab for each eye and pooled for subsequent inoculation, so that the laboratory incurred no additional work. A close correlation was observed between isolation rate, together with the number of inclusions, obtained in cell culture, and intensity of inflammatory disease in hyperendemic trachoma. The sensitivity and practicability of this cultural test should provide a valuable laboratory index for use in epidemiological and therapeutic studies of trachoma.